A support pad, sometimes referred to as a support bar, guide pad, or guide bar is used during cutting in metals and other hard materials on for instance cutter heads of deep-hole drilling tools. The purpose of the support pad is to support and guide the deep-hole drilling tool by sliding against the wall of the hole being drilled, and also to prevent wear of the cutter head.
In addition to the supporting function, the support pad also contributes to finishing and smoothing of the surface of the wall of the hole.
The support pad is subjected to strong wear due to the high temperature load in the contact zone between the support pad and the wall of the hole. The wear and the temperature load constitutes a problem, which can lead to heat cracks in the support surface of the support pad, which eventually could lead to breakage of the support pad.
In the prior art, see below, this problem has been addressed by supplying cooling and/or lubricating liquids to the contact zone in order to reduce the heat load.
 US 2013/0051944 discloses a support guide pad for a rotating cutting tool rotating around an axis of rotation in a rotary direction. The support pad defines a central longitudinal axis and has a first longitudinal edge side, an opposite second longitudinal edge side, a first transversal edge side and an opposite second transversal edge side. The support pad includes a support surface, which is convexly curved as viewed in a plane perpendicular to the central longitudinal axis. Lubricating grooves extends in the support surface in a direction from the first longitudinal edge side. In one embodiment, the grooves extend to the second longitudinal edge side. In another embodiment, the grooves extend to the first transversal edge side.
U.S. Pat. No. 6,602,028 discloses a support pad for a rotating cutting tool rotating around an axis of rotation in a rotary direction. The support pad defines a central longitudinal axis and has a first longitudinal edge side, an opposite second longitudinal edge side, a first transversal edge side and an opposite second transversal edge side. The support pad has a first contact surface and a second contact surface, which are convexly curved.
WO2012/172537 discloses a support pad for a rotating cutting tool rotating around an axis of rotation in a rotary direction. The support pad defines a central longitudinal axis and has a first longitudinal edge side, an opposite second longitudinal edge side, a first transversal edge side and an opposite second transversal edge side. The support pad has a first convex contact surface and a second convex contact surface.
WO 2009/030188 discloses a support pad for a rotating cutting tool rotating around an axis of rotation in a rotary direction. The support pad defines a central longitudinal axis and has a first longitudinal edge side, an opposite second longitudinal edge side, a first transversal edge side and an opposite second transversal edge side. The support pad includes a support surface. Channels for cooling and/or lubricating liquid extend to an area in the proximity of the support pad for cooling and/or lubrication thereof.